Organic oxygen absorber comprising porous carrier and method for preparing the same

ABSTRACT

Disclosed herein are an organic oxygen absorber and a preparation method thereof. The organic oxygen absorber is prepared by reacting each of an ascorbic acid compound and an oxygen absorption promoting material with porous silica powder, which has high adsorbability, at room temperature so as to be impregnated into the silica powder, and then mixing the impregnated materials with each others before filling into an air-permeable packaging material. The organic oxygen absorber does not influence an oxygen detector or the like, has high oxygen absorbability and is prepared with high efficiency.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2013-0023442, filed on Mar. 5, 2013 in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic oxygen absorber comprising a porous carrier and a preparation method thereof, and more particularly an organic oxygen absorber prepared by reacting each of an ascorbic acid compound and an oxygen absorption promoting material with porous silica powder, which has high adsorbability, at room temperature so as to be impregnated into the silica powder, and then mixing the impregnated materials with each others before filling into an air-permeable packaging material, and a preparation method.

2. Background of the Related Art

It is widely known to package foods together with an oxygen absorber in containers in order to prevent the oxidation of the foods during distribution. The oxygen absorber serves to absorb oxygen in the packaging container to make it possible to store foods under oxygen-free conditions. Thus, the use of the oxygen absorber can prevent foods from being deteriorated by oxidation, decomposition, spoiling or the like and makes it possible to distribute foods in a good state over a long period of time.

Known examples of the oxygen absorber include an inorganic oxygen absorber based on iron and an organic oxygen absorber based on an organic antioxidant.

The inorganic oxygen absorber based on iron has been generally used, but it merely absorbs oxygen in a packaging material and does not generate gas corresponding to the amount of oxygen absorbed, and thus causes a shrinkage phenomenon in which the amount of gas in the packaging material decreases. If a product in the packaging material is easily deformed or broken by compression, the product is highly likely to be deformed or broken by the shrinkage phenomenon. In the food processing field, it is performed to check the presence or absence of metallic foreign matter in a packaging material using a metal detector, but the main component (iron) of the inorganic oxygen absorber reacts with the metal detector, and thus is erroneously detected as foreign matter. For this reason, the organic oxygen absorber has a drawback in that it cannot be used in the field that uses the metal detector.

Thus, in fields such as the food packaging field, the iron-free organic oxygen absorber that is not detected by the metal detector has been proposed.

With respect to the organic oxygen absorber, it was proposed to use a titanium dioxide having oxygen vacancies as an oxygen absorber that prevents various articles or goods, including foods, medical supplies, medical drugs, leather products, wood products and precision machines, from being deteriorated by mold, microorganisms, insects and oxidation (see Japanese Patent No. 3288265). The titanium dioxide having oxygen vacancies is prepared by heating titanium dioxide under oxygen-free conditions, and the temperature of the heating is preferably as high as possible in order to increase the ability to absorb oxygen. For this reason, the heating is required to be performed at a temperature of about 800° C.

However, the preparation of the oxygen absorber by high-temperature heating has a problem of a high production cost, and it was reported that, if the heating temperature is as high as 800° C., the crystal of titanium dioxide undergoes the phase transition from anatase to rutile (see, for example, Non-Patent Documents 1: Kozo Tanabe, Tetsuro Kiyoyama and Kazuo Fueki, “Metal oxides and Compound Oxides”, Kodansha Scientific (1978), pp. 103; and Non-Patent Documents 2: Seiichi Nishimoto, Fumiaki Otani, Akira Sakamoto, and Tsutomu Kagitani, Journal of Japanese Chemistry (1984), pp. 246-252). Therefore, heating to around 800° C. is expected to change the oxygen vacancy sites while transforming or changing the crystal structure of the titanium dioxide. For this reason, the amount of oxygen absorbed by the oxygen absorber is reduced and it is difficult to obtain a stable and good oxygen absorber.

Meanwhile, an oxygen absorber based on ascorbic acid, an oxygen absorber based on a phenol derivative, and the like have been proposed (for example, Japanese Patent Laid-Open Publication No. Sho 59-29033, Japanese Patent No. 2658640, and Japanese Patent Laid-Open Publication No. 2000-50849). However, these oxygen absorbers have a slow reaction rate compared to the iron-based oxygen absorber, and thus are required to contain a large amount of water in order to increase the reaction rate. If these organic oxygen absorbers contain a large amount of water, they will have poor flowability, and thus will be significantly difficult to mechanically fill into packaging materials such as small bags.

In addition, the oxygen absorbers start to absorb oxygen during the preparation thereof. In order to prevent oxygen absorption during the preparation process, the oxygen absorbers should be prepared under oxygen-free conditions or the time for the preparation thereof is limited, resulting in a decrease in production efficiency.

Therefore, there is an urgent need for the development of an organic oxygen absorber, which does not influence a metal detector and the like, has high oxygen absorbability, has the ability to generate carbon dioxide gas so as not to cause the shrinkage phenomenon in packaging materials, does not absorb oxygen during the preparation thereof to eliminate the need for equipment that replaces oxygen with nitrogen to provide oxygen-free conditions, and has high flowability so as to be mechanically easily filled in packaging materials such as small bags and to be efficiently prepared.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in order to solve the above-described problems occurring in the prior art and provide various additional advantages, and it is an object of the present invention to provide an organic oxygen absorber, which does not influence a metal detector and the like, has high oxygen absorbability, has the ability to generate carbon dioxide gas so as not to cause the shrinkage phenomenon in packaging materials, does not absorb oxygen during the preparation thereof to eliminate the need for equipment that replaces oxygen with nitrogen to provide oxygen-free conditions, and has high flowability so as to be mechanically easily filled in packaging materials such as small bags and to be prepared with high efficiency, and a preparation method thereof.

The above object is achieved by an organic oxygen absorber comprising a porous carrier and a preparation method thereof according to the present invention.

In one aspect, the present invention provides an organic oxygen absorber comprising a porous carrier, the organic oxygen absorber including: an oxygen-absorbing material prepared by allowing 100 wt % of silica and 100-200 wt % of an aqueous solution of sodium L-ascorbate to react with each other at room temperature so as to impregnate the sodium L-ascorbate into the silica; and a catalyst material prepared by allowing 100 wt % of silica and 100-200 wt % of an aqueous solution of ferrous sulfate heptahydrate to react with each other at room temperature so as to impregnate the ferrous sulfate heptahydrate into the silica, wherein the oxygen-absorbing material and the catalyst material are mixed with each other at a predetermined ratio before filling into an air-permeable packaging material.

In an embodiment of the present invention, the aqueous solution of sodium L-ascorbate may consist of water and sodium L-ascorbate mixed at a ratio of 4:1-1:1.

In another embodiment of the present invention, the aqueous solution of ferrous sulfate heptahydrate may consist of water and ferrous sulfate heptahydrate mixed at a ratio of 8:1-1:1.

In another aspect, the present invention provides a method for preparing an organic oxygen absorber comprising a porous carrier, the method including the steps of: allowing 100 wt % of silica and 100-200 wt % of an aqueous solution of sodium L-ascorbate to react with each other at room temperature so as to impregnate the sodium L-ascorbate into the silica, thereby preparing an oxygen-absorbing material; allowing 100 wt % of silica and 100-200 wt % of an aqueous solution of ferrous sulfate heptahydrate to react with each other at room temperature so as to impregnate the ferrous sulfate heptahydrate into the silica, thereby preparing a catalyst material; and mixing the oxygen-absorbing material with the catalyst material at a predetermined ratio before filling into an air-permeable packaging material.

In an embodiment of the present invention, the aqueous solution of sodium L-ascorbate may consist of water and sodium L-ascorbate mixed at a ratio of 4:1-1:1.

In another embodiment of the present invention, the aqueous solution of ferrous sulfate heptahydrate may consist of water and ferrous sulfate heptahydrate mixed at a ratio of 8:1-1:1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the inventive organic oxygen absorber comprising a porous carrier and a preparation method thereof will be described in detail.

In the present invention, an ascorbic acid compound serving as an oxygen-absorbing material is dissolved in water and reacted with porous silica powder, which has high adsordability, at room temperature so as to be impregnated into the porous silica powder, and the solution is granulated.

Meanwhile, an iron salt compound serving as a catalyst in an oxygen absorption reaction is dissolved in water and reacted with porous silica powder, which has high adsordability, at room temperature so as to be impregnated into the porous silica powder, and the solution is granulated.

Because the oxygen-absorbing material and the catalyst material are separately prepared, the oxygen-material material does not absorb oxygen during the preparation process.

The oxygen-absorbing material and the catalyst material are mixed with each other, and the mixture is filled into a packaging material having air permeability, thereby obtaining an organic oxygen absorber.

The carrier silica (SiO₂—H₂O) that is used in the present invention is also called “silicon dioxide” or “amorphous precipitated silica” and is a material different from the so-called “silica gel” that is frequently used in water absorbents. The silica has a SiO₂ content of 98% or more and is odorless white powder having a particle size of about 200 μm. The silica can be selected as the optimal carrier that is insoluble in both water and general solvents.

Examples of ascorbic acid or its salt which is used as the ascorbic acid compound in the present invention include L-ascorbic acid (vitamin C), ascorbic acid salts such as L-sodium ascorbate, and ascorbic acid salts such as erythorbic acid (isoascorbic acid) and sodium erythorbate.

Examples of the iron salt compound that is used in the present invention include ferrous salts such as ferrous sulfate and ferrous chloride, and ferrite salts such as ferrite sulfate, ferrite chloride and ferrite hydroxide.

In the present invention, 100 wt % of silica is reacted with 100-200 wt % (preferably 130-170 wt %) of an aqueous solution of sodium L-ascorbate (consisting of water and sodium L-ascorbate mixed at a ratio of 4:1-1:1, and preferably 2:1-1:1) at room temperature to impregnate the sodium L-ascorbate into the silica, thereby preparing an oxygen-absorbing material. Meanwhile, 100 wt % of silica as a novel material is reacted with 100-200 wt % (preferably 130-170 wt %) of an aqueous solution of ferrous sulfate heptahydrate (consisting of water and ferrous sulfate heptahydrate mixed at a ratio of 8:1-1:1, preferably 4:1-2:1) at room temperature to impregnate ferrous sulfate heptahydrate into silica, thereby preparing a catalyst material. The prepared oxygen-absorbing material and catalyst are mixed with each other and filled into a packaging material having air permeability.

Example 1

100 wt % of silica was reacted with 148 wt % of an aqueous solution of sodium L-ascorbate (consisting of 74 wt % of water and 74 wt % of sodium L-ascorbate) at room temperature to impregnate the sodium L-ascorbate into the silica, thereby preparing an oxygen-absorbing material.

Meanwhile, 100 wt % of silica was reacted with 148 wt % of an aqueous solution of ferrous sulfate heptahydrate (consisting of 111 wt % of water and 37 wt % of ferrous sulfate heptahydrate) to impregnate the ferrous sulfate heptahydrate into the silica, thereby preparing a catalyst material.

The prepared oxygen-absorbing material and catalyst material were allowed to stand in air for 12 hours, and then 2.0 g of the oxygen-absorbing material was mixed with 1.0 g of the catalyst material.

Comparative Example 1

2.0 g of sodium L-ascorbate and 1.0 g of ferrous sulfate heptahydrate were allowed to stand in air for 12 hours, and then mixed with each other.

Comparative Example 2

100 wt % of silica was mixed with 62.5 g of sodium L-ascorbate, 12.5 g of ferrous sulfate heptahydrate and 75 L of water.

Comparative Example 3

100 wt % of silica was mixed with 62.5 g of sodium L-ascorbate, 12.5 g of ferrous sulfate heptahydrate and 75 L of water. 3 g of the mixture was allowed to stand in air.

Comparative Example 4

100 wt % of silica was reacted with 148 wt % of an aqueous solution of ferrous sulfate heptahydrate (consisting of 111 wt % of water and 37 wt %) to impregnate the ferrous sulfate heptahydrate into the silica, thereby preparing a catalyst material. 2.0 g of the catalyst material and 1.0 g of sodium L-ascorbate were allowed to stand in air for 12 hours, and then mixed with each other.

Experimental Example

The state of the above-prepared mixtures of Example 2 and Comparative Examples 1 to 4 was observed, and each of the oxygen absorbers prepared in the Example and the Comparative Examples was placed in an air-permeable packaging material having a size of 60 mm×60 mm and was then introduced into an air-impermeable 1000-cc container. Then, the amount of oxygen (O₂/CO₂) in the container was measured at various time points using Check Mate 3 (PBI-Dansensor). The results of the measurement are shown in Table 1 below.

TABLE 1 Example 1 Comp. Ex. 1 Comp. Ex. 2 Comp. Ex. 3 Comp. Ex. 4 Weight (g) of mixtures 3.0 3.0 3.0 3.0 3.0 State of mixtures Good/ Good/ Good/ Good/ Agglomerated High High High High and flowability flowability flowability flowability coagulated Amount of After 24 102 0 60 8 90 oxygen hr absorbed After 48 121 0 70 10 100 (cc) at hr 25° C. Compatibility of Compatible Incompatible Incompatible Incompatible Incompatible oxygen absorbers

As can be seen in Table 1 above, the oxygen absorber of Example 1 of the present invention had high oxygen absorbability, showed no decrease in performance when allowed to stand in air, and had high flowability so as to be mechanically easily filled in packaging materials such as small bags, suggesting that it is suitable for use as an organic oxygen absorber.

The material of Comparative Example 1, prepared without reaction and impregnation into silica at room temperature, is unsuitable, because it has no oxygen absorbability.

The organic oxygen absorber compositions of Comparative Examples 2 and 3 started to absorb oxygen during the mixing step. In the case of Comparative Example 3, the oxygen absorbability after standing in air for 12 hours was significantly lower than that before standing in air, like the case of Comparative Example 2. In this case, in order to prevent oxygen absorption during the preparation process (including mixing and packaging), the oxygen absorber should be prepared under oxygen-free conditions or the time for the preparation thereof is limited, resulting in a decrease in production efficiency.

In the case of Comparative Example 4, the particles of the organic oxygen absorber composition agglomerate and stick to each other immediately after mixing, suggesting that the oxygen absorber composition has poor flowability, and thus is not mechanically easily filled into packaging materials such as small bags.

As described above, the organic oxygen absorber according to the present invention does not influence a metal detector and the like, has high oxygen absorbability, has the ability to generate carbon dioxide gas so as not to cause the shrinkage phenomenon in packaging materials, does not absorb oxygen during the preparation thereof to eliminate the need for equipment that replaces oxygen with nitrogen to provide oxygen-free conditions, and has high flowability so as to be mechanically easily filled in packaging materials such as small bags and to be prepared with high efficiency.

While the present invention has been described in connection with the exemplary embodiments illustrated in the drawings, they are merely illustrative embodiments, and the invention is not limited to these embodiments. It is to be understood that various equivalent modifications and variations of the embodiments can be made by a person having an ordinary skill in the art without departing from the spirit and scope of the present invention. Therefore, various embodiments of the present invention are merely for reference in defining the scope of the invention, and the true technical scope of the present invention should be defined by the technical spirit of the appended claims. 

What is claimed is:
 1. An organic oxygen absorber comprising a porous carrier, the organic oxygen absorber comprising: an oxygen-absorbing material prepared by allowing 100 wt % of silica and 100-200 wt % of an aqueous solution of sodium L-ascorbate to react with each other at room temperature so as to impregnate the sodium L-ascorbate into the silica; and a catalyst material prepared by allowing 100 wt % of silica and 100-200 wt % of an aqueous solution of ferrous sulfate heptahydrate to react with each other at room temperature so as to impregnate the ferrous sulfate heptahydrate into the silica, wherein the oxygen-absorbing material and the catalyst material are mixed with each other at a predetermined ratio before filling into an air-permeable packaging material.
 2. The organic oxygen absorber to claim 1, wherein the aqueous solution of sodium L-ascorbate consists of water and sodium L-ascorbate mixed at a ratio of 4:1-1:1.
 3. The organic oxygen absorber to claim 1, wherein the aqueous solution of ferrous sulfate heptahydrate consists of water and ferrous sulfate heptahydrate mixed at a ratio of 8:1-1:1.
 4. A method for preparing an organic oxygen absorber comprising a porous carrier, the method comprising the steps of: allowing 100 wt % of silica and 100-200 wt % of an aqueous solution of sodium L-ascorbate to react with each other at room temperature so as to impregnate the sodium L-ascorbate into the silica, thereby preparing an oxygen-absorbing material; allowing 100 wt % of silica and 100-200 wt % of an aqueous solution of ferrous sulfate heptahydrate to react with each other at room temperature so as to impregnate the ferrous sulfate heptahydrate into the silica, thereby preparing a catalyst material; and mixing the oxygen-absorbing material with the catalyst material at a predetermined ratio before filling into an air-permeable packaging material.
 5. The method of claim 4, wherein the aqueous solution of sodium L-ascorbate consists of water and sodium L-ascorbate mixed at a ratio of 4:1-1:1.
 6. The method of claim 5, wherein the aqueous solution of ferrous sulfate heptahydrate consists of water and ferrous sulfate heptahydrate mixed at a ratio of 8:1-1:1. 